mmRUKSUNIVERSITEIT

GENT

POSITRONANNIHILATION

Editor* L. DORIKENS-VANPRAET, M. DOMKENS and D. SEGERS

Gent, Belgium29 August -

^ , 3 September 1 988

T l I I T TI I T * * 1

INFORIV.A'I\O

World ScientificSingapore • Afew Jersey

TABLE OF CONTENTS

PREFACE vii

SPONSORS viii

COMMITTEES ix

LIST OF PARTICIPANTS xxvii

INAUGURALADDRESS 3

INVITED PAPERS 7

SUMMARIES OF OPEN DISCUSSIONS 207

CONTRIBUTED PAPERS 231

CONFERENCE SUMMARIES 963

AUTHOR INDEX 979

SUBJECT INDEX 985

PAPERS

INAUGURAL ADDRESS

"A mean lifetime with positrons"I.K.MacKenzie

INVITED PAPERS

Low energy positron beams

"Positronium emission spectroscopy" gR.H.Howell, M.Tuomisaari

"Positron channeling in thin Si(100) crystals" 12P.J.Schultz, LR.Logan, M.G.Cottam, T.E.Jackman, J.A.Davies

"Recent results from Giessen" 15F.Ebel, W.Faust, C.Hahn, S.Langer, N.Riickert, H.Schneider, A.Singe, I.Tobehn (speaker: H.Schneider)

"Recent advances in beam technology" 1 gK.F.Canter, G.R.Brandes, T.N.Horsky, P.H.Lippel, A.P.Mills Jr.

"A positronium beam and positronium reflection from LiF(100)" 28M.Weber, S.Tang, S.Berko, B.LBrown, KF.Canter, K.G.Lynn, A.P.MHIs Jr., LO.Roellig, AJ.Viescas

"The status of Japanese work on slow beams" 31T.Akahane, T.Chiba

"Positron factory project in Japan" 34Y.Tabata, S.Okada

XII

Defect studies

"Defect profiling with slow positrons" 39A.Vehanen

"Lifetime spectroscopy in sub-surface defect studies" 52G.Kogel

"Resonance trapping of positrons" 56M.J.Stott

"Gases in metals: interfaces, bubbles and complexes" 60R.Nieminen

"Positronium in voids in metals" 73M.Hasegawa, S.Berko, E.Kuramoto

"Positron studies of precipitation phenomena in Al alloys" 76G.DIubek, R.Krause, G.Wendrock

'The microscopic structure of nanocrystalline materials" 79H.E.Schaefer, W.Eckert, O.Stritzke, R.Wurschum, W.TempI

"Defects in semiconductors" 86S.Dannefaer

"Positron lifetime and charge states of vacancies in as-grown GaAs" 95C.Corbel

'Theory of positron and electron states in semiconductors" 101M.J.Puska

Electronic structure ot matter

"Positron annihilation at Geneva: recent results" 109A.A.Manuel, AXSingh, T.Jarlborg, P.Genoud, LHoffmann, M.Peter

"Recent 2D-ACAR results in highly scattered electron systems from Tsukuba" 119S.Tanigawa

"Electron momentum density studied by high-energy X-ray Compton scattering" 122N.Shiotani, N.Sakai, O.Mao, M.lto, F.ltoh, M.Sakurai, T.Sukawa, H.Kawata, Y.Amemiya, M.Ando.

"2D-ACAR studies of Cu9i-Ge9 and NiMnSb" 125P.E.Mijnarends, K.E.H.M.Hanssen, LP.LM. Rabou, A.Bansil

"Electronic structure of disordered CuPd alloys by positron annihilation 2D-ACAR" 128LC.Smedskjaer, R.Benedek, R.W.Siegel, D.G.Legnini, M.D.Stahulak, A.Bansil

"Momentum distributions in metals and compounds" 131M.Sob

Non-metallic systems

"Positrons and positronium in molecular solids" 137T.Goworek

"Magnetic quenching experiments in condensed matter" 147G.Consolati

XIII

"Positronium in silica aerogel" 1 ._Tianbao Chang

"Phase transition studies in molecular materials and non-metallic systems" 153

Fundamental aspects of positron physics

"Physics in a positron trap" 1 6 1

C.M.Surko, A Passner, M.Leventhal, F.J.Wysocki

"A study of e + e ' interaction in the MeV region" 1 7 1

K.Maier, E.Widmann, W.Bauer, F.Bosch, J.Briggmann, H.D.Carstanjen, W.Decker, J.Diehl, G.FabritiusB.Keyerleber, J.Major, H.E.Schaefer, A.Seeger, H.Stoll

Atomic physics

"Antihydrogen" 181M.Chariton

"Positron scattering theory" ig 1

J.W.Humberston

High Tc superconductors

"ACPAR in high To superconductors" 197M.Peter, L.Hoffmann, A.A.Manuel

SUMMARIES OF OPEN DISCUSSIONS

"Positron and positronium chemistry; round table discussion" 209J.C.Abb§, discussion leader

"Open discussion on experimental techniques and data analysis for bulk systems" 216M.EIdrup (discussion leader), I.MacKenzie, B.T.A.McKee, D.Segers

"Open discussion on positron studies on high Tc superconductors" 227M.Doyama, discussion leader

CONTRIBUTED PAPERS

Electronic structure of matter

"2D-ACAR measurements on the heavy-electron compound URu2Si2" 233G.J.Rozing, LP.LM.Rabou, P.E.Mijnarends, AAMenovsky

"Fourier transform of momentum density in Pd and PdH" 236AKshirsagar, D.G.Kanhere, R.M.Singru

"Fermi-surfaces in rare-earth hexaborides determined by positron 2D-ACAR" 239S.Tanigawa, T.Kurihara, M.Osawa, T.Komatsubara, Y.Onuki

XIV

"Reconstruction of the Fermi-surface of Gd from positron annihilation data" 242A.AIam, R.LWaspe, R.N.West

"Momentum space densities and Fermi surface studies on Ti and Zr" 245R.Suzuki, S.Tanigawa, N.Shiotani, M.Matsumoto, S.Wakoh

"On the reconstruction of electron momentum density" 248K.V.Bhagwat, G.P.Das, V.C.Sahni

"Fermi radius in Pb-ln alloys" 251K.T.Parker, AT.Stewart

"Interaction of positrons with an amorphous metallic alloy" 254M.Szuszkiewicz, S.Szuszkiewicz, J.Chojcan

"Examination of the electronic structure of split-band and VCA alloys by positron annihilation" 257E.Debowska, J.Rudzinska-Girulska

"Electronic properties and thermal stability of Ni^TMsSi^Bu metallic glasses as studied by the PA and DTA 260methods"Z.Michno, T.Gorecki, W.Swiatkowski, A.Baranowski

"Electronic properties of metallic glasses as studied by the PA and Hall-effect methods" 263Z.Michno, T.Gorecki

"Positron annihilation with 4-f electrons: Ce and CeNis" 266T.Jarlborg, AAManuel, M.Peter, D.Sanchez, A.K.Singh, J.LStephan, E.Walker, W.Assmuss, M.Hermann

"Positron annihilation in TiBe2" 269AAManuel, LHoffmann, A.K.Singh, T.Jarlborg, M.Peter, J.LSmith, Z.Fisk, L.M.Pecora, A.C.Ehrlich

"Electron-positron density distributions in simple and transition metals" 272H.Sormann

"Positron annihilation rates in metals and semiconductors" 275A.Seeger, F.Banhart, W.Bauer

"Spin relaxation of positrons in ferromagnets due to scattering between Bloch states" 278R.BIank, LSchimmele, ASeeger

"A study of positron diffusion and localization in a-iron bymeans of e + spin relaxation measurements (e+SR)" 281

F.Banhart, J.Major, A.Seeger

"Application of the theory of liquids to e+-e" interaction in Jellium" 284J.Gondzik, H.Stachowiak

Atomic physics

"Fine-structure transitions and motional Stark-effect in n=2 positronium" 289R.Ley, K.D.Niebling, R.Schwarz, G.Werth

"Photoexcitation and cooling of positronium" 292C.D.Dermer, R.H.Howell, K.M.Jones, E.P.Liang, F.Magnotta, K.Ziock

"Inner shell ionization by electrons and positrons" 295F.Ebel, W.Faust, C.Hahn, S.Langer, M.ROckert, H.Schneider, ASinge, I.Tobehn

"Observation of the difference in the e'-e"/e+-e+ interactions via Au L-shell ionization3 297G.R.Massoumi, W.N.Lennard, P.J.Schultz, LR.Logan

"Reflection of positrons from one dimensional crystals" 300LR.Logan, M.G.Cottam, P.J.Schultz, H.H.Jorch

XV

"A progress report on a source of atomic hydrogen for e+-H scattering" 303G.O.Jones, G.Laricchia, M.Charlton, A.C.H.Smith, T.C.Griffith

"Energy distribution of a Ps beam and its application to measurements of Ps-atom total scattering cross section" 306N.Zafar, G.Laricchia, M.Charlton, T.C.Griffith

"Excitation and ionization cross sections for positrons scattered by helium" 308LM.Diana, R.LChaplin, D.LBrooks, P.G.Coleman, J.P.Howell

"Total cross sections for positronium formation in xenon" 311LM.Diana, D.LBrooks, P.G.Coleman, R.LChaplin, J.P.Howell

Surface physics

"Positron annihilation studies in dealuminated Y zeolites" 317M.Debowska, A.Baranowski, KJerie, B.Sulikowski

"Angular correlation technique for study of thin metal film properties" 320Yu.A.Novikov, V.A.Pindjurin, AV.Rakov, M.K.Filimonov, V.P.Shantarovich

"On the mechanisms of positron interaction and annihilation in silicon and on its surface" 323V.I.Goldanskii, Yu.A.Novikov, A.V.Rakov, V.P.Shantarovich

"Theory of positronium formation spectroscopy" 326A.Ishii, J.B.Pendry, D.K.Saldin

"Theory of the positron surface state with nonlocal positron-electron interactions" 329K.O.Jensen, AB.Walker

"Calculations of angular correlation spectra for defect trapped positron states on metal surfaces" 332AP.Brown, K.O.Jensen, A.B.WaIker

"Angular correlation and lifetime of electron-positron annihilation on surfaces" 335Lou Yongming, Gu Binglin, Zhu Jialin, Lee Chang, Xiong Jiajiong, B.Johansson

"Studies of interfaces by positron implantation" 339JABaker, P.G.Coleman

'Two-dimensional physisorbed N2 on grafoil" 342N.Hozhabri, S.C.Sharma, S.J.Wang

"Krypton physisorption on internal copper surfaces observed by PAT" 345K.O.Jensen, M.EIdrup, S.Linderoth, J.H.Evans

"Physisorptions studied by positron annihilation" 348S.J.Wang, D-M.Zhou, Y.C.Jean

"Positronium formation at graphite surfaces promoted by physisorbed monolayers" 351P.Rice-Evans, KU.Rao, I.Y.AI-Qaradawi

"Positronium emission from alkali nalides" 354M.Tuomisaari, R.H.Howell, T.McMullen

"Positron annihilation induced Auger electron emission" 357A.Weiss, M.Jibaly, Chun Lei, D.Mehl, R.Mayer, KG.Lynn

'The relationship between angular correlation measurements and the densities of noble gas precipitates in metals" 360G.M.Dunn, P.Rice-Evans, J.H.Evans

XVI

Defects

'Trapping model for thermal and nonthermal positrons in metals" 365

E.Gramsch, K.G.Lynn

'Theory of positron trapping by Guinier-Preston zones" 368U.H.GIaser, G.DIubek

"On the structure of jogs at dislocations in Al and Fe as studied by positron spectroscopy" 371C.Hidalgo, S.Linderoth, G.Gonzalez-Doncel, J.San Juan

"A model for positron trapping and detrapping at dislocations and jogs" 374LY.Xiong, C.W.Lung

"Self-localized positron state properties" 377V.M.Osadchiev, S.G.Pozdnyakov

'The dynamics of the self-localized positron state" 380V.I.Meshakin, V.M.Osadchiev, A.V.Shishkin

"Positron annihilation with bound electron" 383V.M.Osadchiev, O.N.Tazetdinov, AV.Shishkin

"Positron annihilation in a FeNi-based amorphous alloy at low temperatures" 386AXLiolios, M.Chardalas, S.Dedoussis, S.Charalambous

"Study of amorphous FeSiB system alloys by positron annihilation technique and resistance measurements" 389Chao Yuesheng, LY.Xiong, Zhang Pingping, Zhu Jie, Zhang Shouguo, C.W.Lung

"Positron trapping in metallic glasses and the crystalline embryos model of their structure" 392Z.Michno

"Defect accumulation during the martensitic transformation in Fe-Mn-Si shape memory alloys" 395J.Van Humbeeck, G.Ghosh, LDelaey, D.Segers, M.Dorikens, LDorikens-Vanpraet

"Variation of microstructural defects in martensite of Cu-base shape memory alloys" 398He Yongshu, Gu Hua, Yang Juhua, Zhau Guangming, Wang Yunyu, Yang Jianhua, Zhao Liancheng, Lei Tingquan

"Effect of vacancy on reversible martensitic transformation in Cu-Zn-AI alloy" 401K.P-fotkowski, TJ.Panek

"Stage II recovery in proton-irradiated aluminium" 404H.Rajainmaki, S.Linderoth

"Positron annihilation in solid and liquid aluminium" 407W.Eckert, H.E.Schaefer

"Defect profiles in ion-implanted copper single-crystals" 410R.S.Brusa, A.Dupasquier, R.Grisenti, S.Liu, S.Oss, A.Zecca

"Distribution of He implanted into metals probed by monoenergetic positrons" 413A.Uedono, S.Tanigawa, H.Sakairi

"Positron annihilation study of helium irradiated nickel foils" 416D.Segers, I.Lemahieu, LDeschepper, M.Dorikens, D.Geshef, LDorikens-Vanpraet, LM.Stals, G.Severne,AHermanne

"Study of thermal equilibrium vacancies in pure iron by positron lifetime spectroscopy" 419Y.Shirai, H.E.Schaefer, ASeeger

"Vacancy migration at high temperatures in Au in fast pulse-heating experiments studied by positron annihilation" 422G.Schmid, H.E.Schaefer

"Study of nitrogen implantation layer and fatigued surface layer in titanium by pulsed monoenergetic positron 425beams"J.D.McGervey, G.Welsch, G.Kogel, D.Schodlbauer

XVII

"Interdiffusion of Ti and Ni sputtered layers monitored by slow positron beam profiling techniques" 428H.Schut, A.van Veen, D.T.Britton, M.A.Hollanders, B.J.Thysse

"On the state of positrons in metallic voids" 431G.Trumpy

"Helium irradiated molybdenum studied by positron annihilation" 434P.M.G.Nambissan, P.Sen, B.Viswanathan

"Helium precipitation and radiation damage in refractory metals" 437P.Sperr, G.Kogel, J.Stormer, W.Triftshauser, R.Lasser

"The study of effect of rare earth atoms on recovery process in deformed 16Mn-steel by positron annihilation" 440Jie Zhu, LY.Xiong, J.Z.Chen, C.W.Lung

"Positron annihilation studies on electrolytically hydrogen charged SS316" 443C.Lopes Gil, M.F.Ferreira Marques, A.P.de Lima

"Positron annihilation ACAR measurement of neutron-irradiated Fe-Cr-Ni alloys" 446E.Kuramoto, N.Kikuchi, D.lrasawa, M.Takenaka, M.Hasegawa

"Studies of neutron irradiated reactor pressure vessel steels by positron annihilation" 449G.Brauer, LLiszkay, B.Molnar, R.Krause, A.Polity

"Doppler-broadening measurements on a neutron-irradiated construction material of pressurized water reactors" 452S.Vass, F.Divos

"Dependence of positron annihilation parameters in the refractory metals on irradiation and temperature" 455N.F.Miron, S.N.Maev

"Investigation of defects in neutron irradiated SiC" 458A.I.Girka, AD.Mokrushin, D.N.Mokhov, V.M.Osadchiev, A.D.Pogrebnjak, AV.Shishkin

"Positron annihilation and vacancies in NiAl and FeAl" 461S.M.Kim

"The anomaly of the Doppler broadened annihilation radiation in dilute aluminum alloys just below the melting point" 464T.Kurihara, S.Tanigawa

"Positron study of aging in the aluminum-based 7012 alloy" 467S.Abis, M.Biasini, ADupasquier, P.Sferlazzo, A.Somoza

"Positron annihilation study of quenched aluminium-lithium alloys" 470H.P.Leighly, P.G.Coleman, R.N.West

"Precipitation of transition elements in rapidly solidified Al alloys studied by positron annihilation, TEM and hardness 473tests"P.Czurratis, E.Korngiebel, G.DIubek, R.Krause, H.Loffler

"Positron annihilation and perturbed angular correlation study of Al-1.5wt% Hf alloy 476D.Vasumathi, C.S.Sundar, G.Amarendra, K.P.Gopinathan

"Investigation of clustering of Ag atoms in Al-Ag alloy by positron annihilation spectroscopy" 479ABharathi, C.S.Sundar

"Vacancy properties in ordered CU3AU and NbAI" 482S.M.Kim

"Experimental evidence for positron trapping at dislocations in Ni3AI alloys" 485S.G.Usmar, KG.Lynn

"Order-disorder transformation and vacancies in CU3AU studied by positron lifetime spectroscopy" 488Y.Shirai, F.Nakamura, M.Takeuchi, K.Watanabe, M.Yamaguchi

"Lifetime and Doppler-broadening measurements in Cu Ge alloys" 491J.KIuin, J.Wolff, W.Luhr-Tanck, T.Hehenkamp

XVIII

"Helium bubbles in Ni and Ni-Ti alloys: effect of titanium on bubble growth" 494G.Amarendra, B.Viswanathan

"Positron annihilation studies of Ni-based dilute alloys" 497Z.Michno, T.Gorecki

"Equilibrium temperature dependence of the characteristics of positron annihilation in Zircaloy-2 and Zr-2.5 wt% Nb" 500G.M.Hood, R.J.Schultz

"Defects in irradiated Zircaloy-2 and Zr-2.5 wt% Nb: a positron annihilation spectroscopy study" 503G.M.Hood, R.J.Schultz

"Positron lifetime study of radiation and annealing effects in V-Ti alloys" 506D.lrisawa, E.Kuramoto

"Positron lifetime in electron irradiated FeNiCr austenitic alloys" 509D.Huguenin, C.Corbel, P.Moser, F.Vanoni

"Bulk-lifetimes and trapping-rates in AgSb alloys" 512W.Luhr-Tanck, ASager, M.Ederhof

'The search for the evidence of the presence of atomic excitons in Pb alloys by positron technique" 515T.Kurihara, S.Tanigawa

"Positron annihilation study of cobalt ZSM-5" 518F.H.Hsu, J.S.Hwang, D.C.Shieh, R.Szostak, T.Thomas

"Positron annihilation in ultrafine metal particles" 521S.V.Svirida, S.Linderoth, I.ARepin

"Study of krypton-implanted molybdenum and titanium with slow positron beam" 524D.LSmith, P.C.Rice-Evans, D.T.Britton, J.H.Evans, AAllen

"Positron beam study of silicon implanted gallium arsenide" 527D.LSmith, P.C.Rice-Evans, GAGledhill, AAllen

Positron and positronium chemistry

"Solvent effect on the Ps quenching reactions with the paramagnetic free radical H-tempo" 531W.F.Magalhaes, J.C.Abbe, G.Duplatre

"Positronium inhibition and reactions in Co(lll) and Cr(lll) acetylacetonates solutions in benzene" 534W.F.Magalhaes, J.C.Abbe, G.Duplatre

"Magnetic and thermal effects on positronium formation and annihilation in organic liquids" 537DADiehl, D.M.Schrader

"Magnetic field effects on positronium" 540I.Billard, J.C.Abbe, G.Duplatre

"Effective radii of some 3d and 4f ions in ortho-positronium spin exchange and oxidation reactions" 543E.Lazzarini, ALFantola Lazzarini

"Linear free energy relationship in positronium complex reaction" 546Yin Dinzhen, Cao Chuan, Chang Tianbao, Wang Shuying, Chen Rongti, Liu Henqian, Liang Jiachang, Du Youming

"On the possible formation of the [Ps Ni (CN)4]2' positronido complex in aqueous solutions" 549E.Lazzarini, A.LFantola Lazzarini

"Positron annihilation in crown-ether/benzene mixtures" 552O.E.Mogensen

"Solid state polymerization studied by positron annihilation techniques" 555S.Millan, V.Sanchez, LAFucugauchi, Y.lto, Y.Tabata

XIX

"Polymerized liquid crystals studied by positron annihilation techniques" 558S.Millan, R.Lopez, J.C.Alvarez, LA.Fucugauchi

"Positronium inhibition by phosphate and ortho-phosphate ions in water at low concentrations" 561FASmith, S.Naidu

"Positronium and muonium reactions in micelles: a kinetic comparison" 564M.V.Barnabas, K.Venkateswaran, D.C.Walker

"Effects of adsorbed ions on the positronium reactivities in porous media" 567Y.C.Jean, K.Venkateswaran, X.H.Luo, K.L.Cheng

"Isomer effect on the reactivity and inhibition capacity of nitrophenols and nitrophenolates towards 570ortho-positronium in methanol solutions"LLevay, B.Levay, A.Vertes

"Positron annihilation analysis on the character of domain structure of segmented polyether polyurethaneureas" 573Yin Chuanyuan, Xu Weizheng, Gu Qingchao, Shen Dexun

"Positron annihilation characteristics in new coordination compounds" 575Shen Dexun, Wang Guanghou, Teng Minkang, Yi Chunyin, Chen Lin, Lo Chenling, Jin Guoxin, Xi Xinquan

Advances in experimental techniques

'The Stuttgart positron beam, its performance and recent experiments" 579W.Bauer, J.Briggmann, H.D.Carstanjen, W.Decker, J.Diehl, K.Maier, J.Major, H.E.Schaefer, A.Seeger, H.Stoll,R.Wiirschum

"Production of intense positron beam using 10OMeVLINAC" 583Y.lto, O.Sueoka, M.Hirose, M.Hasegawa, S.Takamura, T.Hyodo, Y.Tabata

'The Oak Ridge National Laboratory slow positron source" 586LD.Hulett, TALewis, D.LDonohue, S.Pendyala

'The extraction of LINAC-generated slow positrons using the single-gap accelerator technique" 589T.A.Lewis, LD.Hulett, D.LDonohue

"Stretching of slow positron pulses generated with an electron LINAC 592TAkahane, T.Chiba, N.Shiotani, S.Tanigawa, T.Mikado, R.Suzuki, M.Chiwaki, T.Yamazaki, T.Tomimasu

'The use of thin, single-crystal nickel foils as primary positron transmission moderators" 595N.Zafar, J.Chevallier, G.Laricchia, M.Charlton, F.M.Jacobsen

"On positron moderators and re-moderators" 597M.R.Poulsen, M.Charlton, J.Chevallier, B.I.Deutch, F.M.Jacobsen, G.Laricchia

"Positron re-emission microscopy using a high brightness beam" 600G.R.Brandes, ICF.Canter, T.N.Horsky, AP.Mills Jr.

"A 0.5 to 3.0 MeV monoenergetic positron beam" 603H.Huomo, P.AsokaKumar, S.D.Henderson, B.F.Phlips, R.Mayer, J.McDonough, H.Hacker, S.McCorkle,P.Schnitzenbaumer, J.S.Greenberg, M.S.Lubell, K.G.Lynn, A.Vehanen

"An in-line electrostatic positron gun for surface studies" 606I.R.Farthing, P.G.Coleman

"Positrons in mass spectrometry: fundamental experiments in atomic and molecular physics" 609D.M.Schrader

"Positron ionization mass spectrometry" 612D.LDonohue, G.LGIish, SAMcLuckey, LD.Hulett, H.S.McKown, S.Pendyala

"Experimental determination of three quantum annihilation in metal" 615Mbungu Tsumbu, C.Dauwe

XX

'The practicality of high magnification imaging by positron emission" 617LD.Hulett, S.Pendyala

"A theorem for the determination of resolution functions for positron lifetime spectrometry" 620LD.Hulett, S.Pendyala

"Novel analyses of annihilation lineshapes and delay distributions for technological uses" 623C.F.Coleman, S.J.Conchie, F.A.Smith, A.J.Allen

"A new technique for the reconstruction of three dimensional momentum distributions" 626R.Suzuki, S.Tanigawa

"Software correction of electronic drift in positron lifetime spectra" 629J.P.Teixeira Dias, J.Jesus, C.Lopes Gil, AP.de Lima

"Statistical second-order moment sensitivity in Doppler broadening spectra" 632E.Carpintero, D.Otero, A.N.Proto, A.Somoza

"A new technique for momentum and lifetime measurements in positron annihilation" 636A.T.Stewart, B.TAMcKee

"On the data treatment of the positron annihilation time-selecting energy spectrometer-magnetic quenching 639experiment"Wang Shuying, Yiangming ShenTu, Guangming Yang, Chang Tianbao

"PC-PATFIT: a program package for fitting positron annihilation spectra on personal computers" 642P.Kirkegaard, N.J.Pedersen, M.Eldrup

"Numerical evaluation of disturbed positron lifetime spectra" 645H.Sormann, P.Kindl, G.Reiter

"On the performance-characterization of the positron annihilation experimental methods" 648ZKajcsos

"High resolution positron lifetime measurements in non-polar liquids" 651F.M.Jacobsen, O.E.Mogensen, N.J.Pedersen

"Fast timing with Hamamatsu R2083Q photomultipliers" 654J.de Vries, A.Zecca, R.S.Brusa, R.G.Grisenti, S.Oss, A.van Veen

"A microprocessor-CAMAC based bi-dimensional analyser for positron studies" 657G.C.PIain, M.J.D.Stokes, AAlam

"An efficient multiple sealer for the ACAR experiment" 660H.T.Wu, F.Y.Yang, P.KTseng

"On the mathematical processing of experimental spectra within the positron annihilation method" 663V.N.Belyaev, AN.Mikheev

"Multiplate scintillation detector for spectrometers of angular correlation of annihilation gamma quanta" 666V.I.Baskakov, V.N.Belyaev, V.Yu.Kovalen, AP.Melikhov, AG.Tafintsev, K.V.Utolin

Semiconductors

"Positron studies of vacancies in semiconductors" 671R.Wurschum, W.Bauer, K.Maier, J.Major, ASeeger, H.Stoll, H.D.Carstanjen, W.Decker, J.Diehl, H.E.Schaefer

"LCAO calculations of momentum densities in some semiconductors" 674T.Chiba, T.Akahane

'Temperature dependent positron diffusion in semiconductors" 677S.Y.Tang, M.Singh,

XXI

"Valence electron and positron charge distributions in semiconductors" 680H.Aourag, R.N.West, J.H.Kaiser, T.Kobayasi

"Evidence of Hg-vacancies in CdHgTe by positron annihilation and the determination of the corresponding specific 684positron trapping rate"R.Krause, A.Polity, A.KIimakov, M.Schenk

"Positron annihilation study of defects in electron irradiated silicon" 687Motoko-Kwete, D.Segers, M.Dorikens, L.Dorikens-Vanpraet, P.CIauws, I.Lemahieu

"lon-implantation-induced damage in Si studied by monoenergetic positrons" 690A.Uedono, S.Tanigawa, J.Sugiura, M.Ogasawara

"Positron energy bands and wave functions in a Si crystal" 693C.Pennetta, A.Baldereschi

"Measurement of positron mobility in silicon by a lifetime method" 696R.I.Simpson, M.G.Stewart, C.D.Beling, M.Charlton

"Non-destructive testing of silicon single crystals by positron annihilation" 699M.Doyama, Y.Suzuki, S.lshibashi, T.Abe

"Characterization of porous silicon by positron lifetime spectroscopy" 702R.M. de la Cruz, R.Pareja

"Effects of boron doping on the annealing characteristics of Cz-silicon" 705W.Puff, P.Mascher, D.Kerr, S.Dannefaer,

"Slow positron defect profiling of silicon epilayers" 708E.Tandberg, P.J.Schultz, T.E.Jackman, M.W.Denhoff, G.C.Aers, K.G.Lynn, B.Nielsen

The accumulation and inversion states of SiO2/Si interface of MOS structure investigated by a variable-energy 711positron beam"A.Uedono, S.Tanigawa, Y.Ohji

"Shallow positron traps in gallium arsenide" 714S.Dannefaer, P.Mascher, D.Kerr

"Positron annihilation in alloy semiconductors and GaAs" 717H.Numata, T.Shimizu, H.Matsuoka, M.Matsui, M.Doyama, T.Hibiya, H.Watanabe

"A study of annealing behaviour and epitaxy process of GaAs by positrons" 719Wu Fengmei, Shen Dexun, Deng Mingkang, Chen Ling

"Positron trapping by charged vacancies in GaAs" 721R.Krause, APolity, G.DIubek, K.Friedland, R.Rentzsch, W.Siegel, G.Kuhnel

"Positron lifetime studies of selenium" 725I.T.Penfold, P.S.Salmon, K.O.Jensen, P.G.Coleman

"Positron trapping in electron-irradiated InSe" 728R.M.de la Cruz, R.Pareja, ASegura, P.Moser, C.Corbel, A.Chevy

"Positron trapping in electron irradiated CdTe and CdTe(ln)11 731A.Sen Gupta, P.Moser

Fluids

"Slowing down of positronium in gases" 7 3 7

M.Kakimoto, Y.Nagashima, T.Hyodo, KFujiwara, T.Chang

"Chemical dynamics of positronium atom in liquids" 740H.Nakanishi, S.J.Wang, Y.C.Jean

XXII

'Theory of self-trapping with a realistic equation of state" 743B.N.Miller.T.LReese

"Angular correlation study of positronium formation in xenon" 746M.Kakimoto, T.Hyodo

"Positron annihilation and Ps formation in xenon" 749M.Tuomisaari, K.Rytsola, P.Hautojarvi

"Effect of density fluctuations on O-Ps annihilation characteristic in fluids" 752T.Siili, M.Tuomisaari, R.M.Nieminen

"Ortho-para conversion of positronium in oxygen studied by the angular correlation method" 755M.Kakimoto, T.Hyodo, T.Chiba, T.Akahane, T.B.Chang

"Positronium reactions in C0CI2 and C1CI3 aqueous solutions: magnetic quenching results" 758G.Consolati, F.Quasso

"Study of water-glyme liquid mixtures by using positron annihilation technique and surface tension measurements" 761J.C.Machado, A.Marques Netto, AS.Reis Jr.

"Orthopositronium diffusion properties and micellar size determined from lifetime experiments in sodium 764dodecylsulphate solutions"S.Vass, Z.Kajcsos, B.Molnar

"Dependence of ortho-positronium pick-off annihilation lifetime on free volume in water-alcohols mixtures" 767KJerie

"Investigation of structure of water-alcohol systems using positron annihilation and compressibility methods" 770KJerie, ABaranowski, B.Rozenfeld, J.GIinski

Non-metallic solids

"Positron bound states in the proximity of two unpaired-spin electrons" 775R.S.Brusa, ADupasquier, S.Oss

"Positron annihilation study of polymer physics" 778A.V.Goldanskii, V.AOnischuk, V.P.Shantarovich

"Determination of free-volume properties in polymers by positronium annihilation spectroscopy" 781H.Nakanishi, Y.Y.Wang, Y.C.Jean, T.C.Sandreczki, D.P.Ames

"Pressure effect on glass transition and on thermal expansion of free volume in amine-cured epoxy studied by 784positronium"Yun Yu Wang, Y.C.Jean

"Effect of pressure on structure of amine-cured epoxy polymer studied by positronium" 787Y.C.Jean, Yun Yu Wang

"An investigation of the nature of the middle lifetime component of positron annihilation in teflon" 790Wang Shuying, Chang Tianbao, Yianming ShenTu, Haidong Wang, Guangming Yan

"Electric-field dependence of positron annihilation in polyethylene" 793A.Cornaz, J.Brunner, E.Cartier

"Size of voids in polyethylene" 796J.C.Abbe, G.Duplatre, J.Serna

"A positron annihilation lifetime study of thermal response and isothermal relaxation in atactic polystyrene" 799A.D.Kasbekar, P.LJones, ACrowson

"Positron annihilation studies in 6OCB" 803C.Kaur, J.Kumar, P.C.Jain

XXIII

"Positron lifetime investigations on polymethylmethacrylate" 806P.Kindl, G.Reiter

"Vacancy formation energy in molecular solid methane studied by positron annihilation" 809S.J.Wang, Y.C.Jean

"Physical aging of poly(vinyl acetate) studied by positron annihilation" 812Y.Kobayashi, W.Zheng, E.F.Meyer, J.D.McGervey, AM.Jamieson, R.Simha

"Positron annihilation studies in solid lanthanides trisdipivaloylmethanates [Ln(dpm)3]" 815A.Marques Netto, M.E.S.R.Silva, J.C.Machado, S.M.C.Maximo Bicalho, J.C.Abbe\ G.Duplatre

"Positron annihilation studies in CTAB reverse micellar systems" 818S.R.Choudhury, R.Yadav, A.N.Maitra, P.C.Jain

"Positron annihilation studies in aerosol OT reverse micellar systems" 821S.R.Choudhury, M.Zaboli, A.N.Maitra, P.C.Jain

"Positronium in sepiolite crystalline fibers" 824Y.Tsuchiya, Y.Kitayama, M.Hasegawa

"Positron annihilation studies in cotton fibre" 827S.ATishin, A.R.Grupper, S.N.Vassermann, V.P.Shantarovich

"Magnetic quenching study of synthetic zeolites" 830Y.lto, M.Hirose, Y.Tabata, M.Hasegawa

"A study of defects in metal oxides by positron annihilation" 833M.Forster, J.N.Mundy, H.E.Schaefer

"A study of sintering processes in ZnO" 837J.del Rio, P.Fernandez, N.de Diego, J.Uopis

"Surface effects on positron annihilation characteristics in CAB-O-SIL (S!O2)" 840F.H.Hsu, M.J.Shao, LD.Hulett, T.M.Rosseel, J.M.Dale

"Evidence for [4:1] defect clustering in CoO revealed by 2D-ACAR measurements" 843T.Chiba, T.Akahane

"Study of positronium states in Kl by using magnetic field" 845T.Hyodo, M.Kakimoto, Y.Nagashima, K.Fujiwara

"Study on KCI colorated center crystal by positron annihilation" 848Huang Maorong, Gu Hua, Wang Yunyu, Zhou Guangmin, Yang Juhua, Lin Jianmin, Xu Chenghuang

"Solid-solid phase transitions and molecular motions in long-chain paraffins studied by positron annihilation 851techniques"B.Levay, M.Lalovic, H.J.Ache

"Observation of short time constant polarization in paraffin wax using positron annihilation" 854R.J.Stone, I.K.MacKenzie, J.E.Bali

"Evidence of a thermally-activated positron motion in paraffin wax" 857J.E.Ball, IXMacKenzie, R.J.Stone

"A positron annihilation study of polymorphism in some even-n fatty acids" 860W.W.Walker

"On positron annihilation lifetimes in heat-treated neutron-irradiated alpha quartz" 863C.Laermans, A.Vanelstraete, D.Segers, M.Dorikens, LDorikens-Vanpraet, J.Cornelis, A.Van den Bosch

"A lifetime and three quantum study of the brittle to plastic phase transition in Norbornane" 866C.Dauwe, Mbungu Tsumbu

XXIV

"Positron annihilation in kapton foils" 869KPIotkowski, T.J.Panek, J.Kansy

"Doppler broadening studies of anthracene single crystal" 872Y.T.O'Yang, M.C.Shih, S.F.Tsai, S.Y.Chuang, P.KTseng

"Positron annihilation in ternary graphite intercalation compounds" 875H.Murakami, M.Sano, I.Kanazawa, T.Enoki, H.lnokuchi

"Relaxation of the momentum distribution of free positronium atoms interacting with silica fine particles" 878T.Hyodo, M.Kakimoto, T.B.Chang, J.Deng, T.Akahane, T.Chiba, B.T.AMcKee, A.T.Stewart

"Study of Gd3GasOi2 crystal doped with Ca2 + by positron annihilation" 881Huang Maorong, He Yongshu, Gu Hua, Wang Yunyu, Zhang Lehui, Lin Chengtian, Liu Hairun

"Positron annihilation study of vacancy defects in doped B—C2S powder sample" 884Shen Dexun, Teng Minkang, Yin Chuanyuan, Shi Yi, Feng Xiuji, Long Shizong

High Tc superconductors

"High Tc superconductors studied by positron lifetime measurements" 889Z.Kajcsos, K.Suvegh, AVertes, T.Porjesz, J.Kirschner, I.Halasz, K.Fischer, W.Zinn

"Positron lifetime calculations for YBa2Cii3O7-S" 892K.O.Jensen, R.M.Nieminen, M.J.Puska

"Positron annihilation study of the YBaCuO high Tc superconductor" 895AK.Liolios, S.Dedoussis, M.Chardalas, C.A.EIeftheriades, D.Niarchos, S.Charalambous

"Positron annihilation in YBazCuaOz: 2D-ACPAR calculations" 898T.Jarlborg, AAManuel, M.Peter, A.K.Singh

"Oxygen vacancies as possible positron trapping centers in Y-Ba-Cu-0 high TC superconductors" 901AG.Balogh, W.Puff, LLiszkay, B.Molnar

"Positron studies in as-received and electron-irradiated YBa2Cu3O6.9, DyBa2Cu3O6.9 and CaSr2Bi2Cu2Os-5" 904P.Moser, J.Y.Henry

"Positron trapping in sintered YBCO" 907R.S.Brusa, ADupasquier, R.Grisenti, S.Liu, S.Oss, A.Zecca

"Electronic structure, momentum density and positron experiments in YBa2Cu3O7" 910A.Bansil, R.Pankaluoto, R.S.Rao, P.E.Mijnarends, W.DIugosz, R.Prasad, LC.Smedskjaer

'Temperature dependent positron-electron momentum densities in YBa2Cu3O7-x by 2D ACAR" 913E.C.von Stetten, S.Berko, X.S.Li, LF.Schneemeyer, J.Brynestad, D.Singh, H.Krakauer, W.E.Pickett, R.E.Cohen

"Fermi surfaces in YBa2Cu3Ox" 916LC.Smedskjaer, J.Z.Liu, R.Benedek, D.G.Legnini, D.J.Lam, H.CIaus, ABansil

"Electronic structure studies of high-Tc perovskites and related materials" 919ALWachs, P.E.ATurchi, J.H.Kaiser, R.N.West, R.H.Howell, Y.C.Jean, K.LMerkle, A.Revcolevschi, M.J.FIuss

"A systematic study of high temperature superconductivity by positron annihilation spectroscopy" 922Y.C.Jean, H.Nakanishi, J.Kyle, S.J.Wang, P.E.ATurchi, R.H.Howell, A.LWachs, M.J.FIuss, R.L Meng H P HorJ.Z.Huang, C.W.Chu

"Positron lifetime spectroscopy on high-Tc superconductor ABa2Cu3C7-8 (A=Y, Eu)" 925S.lshibashi, Y.Suzuki, H.Maruyama, R.Yamamoto, M.Doyama

"Positron annihilation in high Tc Ba-Y-Cu-O" 928M.Matsui, H.Numata, H.Matsuoka, T.Shimizu, M.Doyama, S.lshibashi,Y.Suzuki, R.Yamamoto

"Positron annihilation in Bi-Sr-Ca-Cu-0 high Tc superconductors" 931M.Doyama, M.Matsui, H.Numata, J.Liu, H.Matsuoka, T.Shimizu

XXV

"Fermi surfaces in high temperature superconductors by positron 2D-ACAR" 933S.Tanigawa, Y.Mizuhara, T.Kurihara, M.Osawa, Y.Hidaka, M.Oda, Y.Enomoto, M.Suzuki, T.Murakami

"A sharp peak of the S-parameter near the superconducting transition temperature in YBa Cu 0 " 936Y.Zhang, X.Mao, J.Zhu, C.W.Lung

"The influence of twinning in YBa2Cu3O7 on positron annihilation parameters" 939S.G.Usmar, KG.Lynn, A.R.Moodenbaugh, M.Suenaga, R.LSabatini

"Fermi surface smearing in high temperature superconductors by 1D-ACAR" 942T.Nagarajan, S.Srinivasan, V.Sridharan, V.Prabha, G.V.Subba Rao, U.V.V.Raju, R.Vijayashree

"Positron annihilation study of oxygen vacancies in Y1 Ba2Cu3C7-x" 945A.Bharathi, C.S.Sundar

"The study of high-temperature superconducting YBa2Cu3O7 ceramics using the positron annihilation method" 948V.N.Belyaev, A.N.Mikheev, P.N.Sukharev, Yu.V.Shtotsky

Positron emission tomography and biological systems

"On the robustness of iterative maximum-likelihood reconstructions of PET images against noisy attenuation 953correction measurements"F.L.Vermeulen, I.Lemahieu

"A new system for high resolution PET imaging" 956B.T.AMcKee

"Positron lifetime measurements in organic materials with a ^Na-source" 959F.Ebel, W.Faust, C.Hahn, H.Schneider

CONFERENCE SUMMARIES

Conference summary: "Nonmetals, positronium chemistry, biological applications" 965V.P.Shantarovich

Conference summary: "Low and high energy positron beams: an evaluation of presentations at the ICPA-8" 971W.Triftshauser

INDEXES

Author index ^Subject index a B 5